Collimation tools (split from Lightbridge Updates)

[Starkler (Geoff)]

Originally Posted by Isdonisgood

I think all retailers I have spoken to have suggested a laser first.

You can live without ever owning a laser and have a well collimated scope with just a combo cheshire sight tube. The reverse cannot be said.

[Sentinel]

Scott,

I have a 1 1/2 Orion Sight Tube/Cheshire for placing the secondary. Once that is showing the secondary in under the focuser, I then switch to the Laser, adjust the secondary till the laser is inside the reinforcing ring. Then switch the the Barlowed Laser.

Surely the Sight tube gets used the least. Once the secondary is even/circular under the focuser, surely this is a fairly redundant item. I always store the 1 1/2 Orion Sight Tube/Cheshire in the scope when not in use.

The Orion Sight Tube/Cheshire has too much parallax error really for collimation, however this was my only form of collimation aid for nearly 7 years.

Thanks.

Originally Posted by Tannehill

I have a glatter laser, also, and the Catseye triad of tools. A barlowed laser serves the same function as the Chesire, so if you want to avoid duplication, then you can avoid buying a Chesire.

A sight-tube and an autocollimator complement the Laser + barlow attachment nicely. Each has a purpose not served by the other two. So, if you want a high quality sighttube - one with a telescoping inner tube so as to make secondary placement very simple, get a sight-tube from him...it's quite nice, really, and easily adjusted for different scopes.

The autocollimator is great for fine tuning collimation by adjusting the secondary screws. It's really valuable for faster f-ratio scopes, and less noticeably beneficial for f6 and greater scopes. But if you dial in the AC, you'll be spot on. When using the AC, the fine adjustments you make to the secondary often require you to repeat the primary collimation a bit, then again to the AC. 2-3 iterations at most is necessary for this, but then you are about as perfect as you can be. Assuming your center dot is centered!

if you get the Catseye autocollimator, I'd suggest requesting the WHITE reflective triangles rather than red. Red is fine, but in truth, it's harder to see depending on lighting conditions. If it's daylight, the red is harder to see in the eyepiece, whereas the white reflective is visible in all conditions.

Scott

[Tannehill]

Yep, I agree with Geoff, the laser is not a critical, if I had to have just one single tool it'd be a sight-tube/chesire dual tool. But I like the lasers. And it is - as you point out - real slick for that first-off adjustment of the secondary using the straight beam. I know what you mean about the parallax issue. Catseyes are as good as any, but that still is present to some degree, the separate tool for each is better I reckon. I, too, don't use my sight tube much, except when I've removed the secondary for a reason and replace it. In fact, I use it more for helping others position their secondary than on my scopes, now. And my daughter runs around with it pretending it's a telescope (like I'm gonna let her run with any of MY real stuff...NOT!)

there are so many schools of thougth out there, it's easy to see why the newbies get confused. 25 years ago, when an f5 newt was "fast", it was all eyeballed. Now we have whole websites and instruments devoted to collimation using one of no less than three possible and distinct "religions" of collimation practice. Sheesh.

Cheers,


Scott